PR259WA01 is a passive unit designed for dedicated subwoofer applications - as partner for our active subwoofer units.Due to low mechanical losses it masters equally well low level details and extreme dynamic requirements.For demanding sub bass applications using a passive unit is usually the only real alternative to sealed enclosures with active bass boost.To make experimenting and individual tuning convenient and easy, PR259WA01 is delivered with three separate extra loads that are easily applied onto a threaded rod on the rear side of the cone.